Oxidative dehydrogenation process of aromatic compounds

ABSTRACT

Oxidative dehydrogenation process of aromatic compounds is provided by oxidatively dehydrogenating (1) nuclear substituted ethyl benzene compound of the formula:   (wherein X is lower alkyl radical or halogen atom) or (2) cumene or a nuclear substituted cumene of the formula:   (wherein Y is hydrogen atom, lower alkyl radical or halogen atom) IN THE PRESENCE OF A PHOSPHORUS-TIN ALUMINUM OXIDE CATALYST CONTAINING 10 TO 40 WEIGHT PERCENT OF PHOSPHORUS CALCULATED AS P2O5, 10 to 40 weight percent of tin as SnO2 and 40 to 60 weight percent of aluminum as Al2O3.

United States Patent [191 Sato et al.

l l OXIDATIVE DEHYDROGENATION PROCESS OF AROMATIC COMPOUNDS [75] Inventors: Haruhito Sato; Nobuaki Shimizu;

Kosaku Hanna; Konomu Kurisawa, all of Chiba. Japan [301 Foreign Application Priority Data Jun, 22, 1973 Japan i i v i 4 7. 48-9330 [52] [3.5. CI 260/650 R; 252/437; 260/669 R [5 [1 Int. Cl. C07C 5/48; CO7C 25/28 [58] Field of Search i. 260/650 R, 669 R, 680 E; 252/437 [56I References Cited UNITED STATES PATENTS 3,320,329 5/l967 Nolan 260/680 E 3,497,564 2/1970 Allen et al. 260/650 R 3 679 6Ul 7/l972 Nolan et ail. i i i i 4 H 252/437 1732317 S/l973 Pitzcr v v 260/680 E 3801,67 4/1974 Marsheck 260/680 E Primary Examiner-Paul M. Coughlan, Jr. Arlurm v AgenL ur Firm-l /lcGlew and Tuttle [57] ABSTRACT Oxidativc dehydrogenation process of aromatic com- 1 Oct. 7, 1975 pounds is provided by oxidatively dehydrogenating l) nuclear substituted ethyl benzene compound of the formula:

CH tCH, (I)

(wherein X is lower alkyl radical or halogen atom) or (2) cumene or a nuclear substituted cumene of the formula:

CH ,CHCH ill) (wherein Y is hydrogen atom, lower alkyl radical or halogen atom) in the presence of a phosphorus-tin aluminum oxide catalyst containing 10 to 40 weight percent of phosphorus calculated as P to weight percent of tin as SnO- and 40 to 60 weight percent of aluminum as A1 0 v 4 Claims, N0 Drawings OXIDATIVE DEHYDROGENATION PROCESS OF AROMATIC COMPOUNDS BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an oxidative dehydrogenation process of aromatic compounds. More particularly, it relates to an oxidative dehydrogenation process of aromatic compounds by oxidatively dehydrogenating (1) nuclear substituted ethyl benzene of the formula:

(wherein X is a lower alkyl radical or halogen atom) or (2) cumene or its nuclear substituted products of the formula:

(wherein Y is a hydrogen atom, lower alkyl radical or halogen atom) in the presence of a phosphorus-tin-aluminum oxide catalyst containing 10 to 40 weight percent of phosphorus calculated as P to weight percent of tin as SnO and 40 to 60 weight percent of aluminum as M 0 2. Prior Art The conventional process of oxidative dehydrogen ation of nuclear substituted ethyl benzene or cumene or its nuclear substituted products of the aforementioned general formulae (I, II) is known. Also, the method of transforming these compounds I and II to the corresponding styrene derivatives is according to the prior art.

With regard to the oxidative dehydrogenation process of such aromatic compounds, many studies have been done to develop a novel catalyst because the main technical problem therein is to develop such a catalyst as shows long catalytic life and greatly improves the conversion ratio and selectivity of the reaction. And as a result of such studies, various catalysts have been proposed.

However, the various catalysts hitherto proposed are not satisfactory when evaluated from the industrial viewpoint. For instance, alumina catalyst or phosphorus-tin catalysts are proposed, but the former possesses the defect that catalytic life is short and the latter that the conversion ratio to the desired product is extremely low. Therefore, it is very disadvantageous to apply and use these types of catalyst industrially.

We, the inventors herein have made incessant and concentrated studies on developing a catalyst for the oxidative dehydrogenation reaction overcoming the aforementioned defects. As a result thereof, it has been found that a phosphorus-tin-aluminum oxide catalyst containing phosphorus, tin and aluminum at the ratio specified herein is suitable for the desired purpose and we completed the present invention based on this discovery.

SUMMARY OF THE INVENTION Though the catalytic structure of phosphorus-tinaluminum oxide used as a catalyst in this invention and the oxidation state of these elements have not yet been clearly explained, in any event it is believed that the catalyst of this invention is either a mixture or a compound containing these three elements in the form of an oxide. In this case, in order to obtain high catalytic activity, it is necessary to limit (a) the phosphorus content to from 10 to 4O 7: by weight calculated as P 0 (b) the tin content to ID to 40 '72 by weight as SnO and (c) the aluminum content to from 40 to 6O 7! by weight as AI O The catalyst with such a composition not only improves the conversion ratio and selectivity of the reaction but makes it possible to carry out the reaction at relatively low temperatures because its catalytic activity is excellent at such low temperatures.

DESCRIPTION OF THE INVENTION Phosphorus-tin-aluminum oxide catalyst which are used in this invention can be prepared by mixing alumina sol or aluminum hydroxide, tin hydroxide and phosphoric acid in a predetermined ratio so ethyl the elementary composition of the catalyst which is finally obtained is within the aforementioned ranges, and then calcining the so-obtained catalytic composition or mix turc.

Aromatic compounds applied to the dehydrogen ation process of this invention are those expressed in the aforementioned general formulae (I) and (II), for instance, methyl ethyl benzene, diethyl benzene, iso propyl ethyl benzene, t-butyl ethyl benzene, chloro ethyl benzene, cumene, methyl isopropyl benzene, chloro isopropyl benzene, and mixtures thereof are usefulv All of these aromatic compounds can be converted to the corresponding styrene derivatives with a favorable yield by the process of this invention.

Oxygen or air is used as the oxygen source in the oxi dative dehydrogenation reaction of this invention. In this case, it is possible to use nitrogen or water as a diluent for the purpose of controlling local heating of the catalyst layer and for preventing the explosion of reactants.

The reaction is recommended to be carried out under normal pressure at a temperature of from 350 to 550C, preferably from 400 to 450"Cv In this invention, one of the big advantages obtained by using the catalyst of this invention is that the oxidative dehydrogenation reaction can be carried out at relatively low temperatures of from 400 to 450C.

As for the reaction method, either a fixed bed or a fluid bed can be used. The ratio of the amount of catalyst compared with the amount of supplied raw material per hour is recommended to be selected within the range of from L0 to 15.0 g.mol .hr., preferably from 5.0 to 10.0 g.mol".hr. The partial pressure ratio of aro matic compounds/oxygen in the reaction system is recommended to be from l/0.2 to 1/15, preferably from 1/05 to 1/11).

The present invention is further illustrated in the following examples.

EXAMPLE I To 800 g of alumina sol containing 10 "/r by weight T A B L E 2 -Continued At R mm R of alumina (A1 325.8 g of tin hydroxide 16.7 "4 g am; by weight as SnO of gel form obtained by treating Catalyst subfilwice r ty n Selec- SnCl .2H O with aqueous ammonia and washing with 5 (as M201 Derwm'ves distilled water. and 41.5 g of phosphoric acid with 85 wt 71 1 mol 71 1 m l concentration by weight were added. The mixture 1 was fully kneaded and mixed with kneader. then dried h] M -L' OH, 31'

at 120C. Subsequently it was calcined for 3 hours at 10 3 WWW f t 800C to make catalyst, in which phosphorus, tin and P y t i' ethyl benzene 32.0 styrene 80.0 aluminum were contained respectively at the ratio of 16 71 (as P 0 34 W (as SnO and 50 (as A1 0 p-ehloro pchluru ethyl benzene 43.0 styrene 75.0 by weight In the next place, oxidative dehydrogenation reaction [5 EXAMPLE 3 of various aromat c compounds was carried out with 2.111 In Same way as Example 1! the Gladys m fixed in the presence o1 water as diluent m atixed bed us ng m Oft-m/uluminum (ratio by weight as SnOJAhO: the thus obtained catalyst. The conditions of reaction 5 50 but with Various Contents of pl-logphoruS was and results are shown in Table 1. prepared Water was used as diluent in Example 1 at the ratio The dehydrogenation reaction of aromatic comof 3 mols to 1 mol of aromatic compound. The atomic pound was carried out with such catalyst under the ratio of tin/phosphorus (Sn/P) in catalyst was 1. same conditions as those in Example 1 (provided that TABLE 1 Reaction Condition Conversion Reaction Product De- Reactant Temperature Time Oxygen/ Quantity Ratio of Styrene Selectivity of compoeontinucd Reaetant of Catalyst Reactant Derivatives Styrene sition Derivatives Rate 1hr.) (molar ratio) (gmol hr) (mol 9'!) (mol 9t) (mol '2) ethyl benzene 450 10 0.50 10 42.0 92.0 7.0 1.00 10 55.11 styrene 85.0 13.0 o methyl ethyl 450 10 0.51 1(1 22.0 o-methyl 69.0 18.0 benzene styrene p-t butyl ethyl 450 10 (1.51 10 29.0 pt-butyl 91.0 811 ben/ene 1.05 10 43.0 styrene 87.0 13.0 p-chloru ethyl 450 10 0.51 10 51.0 p-chloro 88.0 6.0 hen/ene 0.99 10 66.0 styrene 82.0 12.0 euniene 450 10 0.50 10 27.0 a-methyl 86.0 13.0 1.03 10 35.0 styrene 72.0 25.11

EXAMPLE 2 the mol ratio of o laromatic compound is 1.0). The re- 40 salt is shown 1 1n the same way as Example 1. the catalyst with fixed n Tdbk' 3 ratio of tin/phosphorus (ratio by weight as SnO /P O T A B L E 3 52/48) but with various contents of aluminum was prepared. Phosphorus The reaction was carried out with such catalyst under Content or Rvucumt R i n Prod ct 3 3 I Catalyst Conversion Styrene Selecthe same conditions as those in Example 1 (provided Suhsmnw Rum Dcrivmivcs why that the mol ratio of oxygen/aromatic compound is (as P 05.

. I r r 1.0). The result 15 shown in Table 2. M J (mm A) ("10] q p-t-butyl p tbuty1 T A B L E ethyl benzene 22.0 styrene 77.0

. I p-chloro p-chloro fi luminiuni Reactant Reaction Product ethyl hcnzcng 44.0 None 740 ontent of puma), y

Catalyst Substance Conversion Styrene Selecethyl hcnzcnc 43.0 styrene 86-0 Ratio Derivatives tivity 10 (as A120,.

x I. p-chloro pchloro I 1 1 1 3 ethyl benzene fill) styrene 81.0

pt-butyl p-t-butyl th 1 be en 44.0 .t 86. p t butyl P b 'v In L y n/ c s yrcnt 0 ethyl benzene 28.0 styrene 87.0 u p ch|om ethyl benzene 65.0 styrene 82.0

p chloro p-ch1uro 6O pvtyhutnfl p 1 buty| m hen/fin? Hymn: ethyl benzene 36.0 styrene 87.0 p-tbutyl p-t-butyl 3U ethyl benzene 42.0 styrene 87.0 h| pchloro 40 ethyl benzene 63.0 styrene 82.0

pchloro p-chloro -bbutyl p-t-butyl ethyl benzene 60.0 styrene 31-11 ethyl benzene 27.0 styrene 85.0 p-bbutyl p-t-hutyl 6Q 40 ethyl benzene 43.0 styrene 87.0 p-chloro hl r S0 ethyl benzene 58.0 styrene 80.0

p-chloro p-chloro p-bbutyl p-t-butyl ethyl benzene 66.0 styrene K111 ethyl benzene 25.0 styrene 83.0 p-t-butyl p-t-butyl 50 ethyl benzene 45.0 styrene 87.1) p'ehloro p-chloro Llilyl uui vMic .14. mymnL r 111* EXAMPLE 4 In the same way as Example I, the catalyst in which the ratio of phosphorus/aluminum was fixed (ratio by weight as P O /Al O 40/60) but the content of tin was varied was prepared.

The dehydrogenation reaction of aromatic compound was carried out with such catalyst under the same conditions as those in Example l (provided that mol ratio of oxygen aromatic compound is L0), The result is shown in Table 4.

'l A B L E 4 Tin ('ontent of Reactant Reaction Product (atalyst Contersion Styrene Selee- Substance Ratio Dermatiyes ti ily (as St \tt 'i i 1 mol '1 l mol ,2

pt hutyl p-t-htttyl ethyl ben/ene 320 st rene H31) ll p-ehloro p-chloro ethyl hen/ene 490 styrene 78.0 p-t-butyl p-t-but \l eth \l lien/.ene 40.0 styrene H50 ll) p chloro p-chloro ethyl lien/cite (il 0 st) rene NH) ptbutyl p-t-butyl eth \l ben/ene 45 I) styrene 870 211 p chloro p-chloro ethyl hen/ene b7 0 sty rene H370 p-t-but tl P-t-l1lll)l ethyl ben/ene 410 styrene K7 0 3o -ehloro p'chloro cth \l ben/ene 62 ll st) rene N10 p-t-bntyl p-t-butyl ethyl lien/cite 44 ll styrene Hot) 4|) p'chloro p-chloro ethyl hen/cue 50,0 styrene X0 0 p t buttl p-t-buttl ethyl bcn/enc 30,0 styrene 310 (\ll -ehloro p-chloro ethyl hen/cue 40 styrene 78.0 p-t-butyl p-tbutyl ethyl ben/enc l5 0 styrene 7h.(l lllll p chloro P-CltlUrU ethyl ben/ene 3h 0 styrene 73.0

We claim:

I. Process for oxidatiye dehydrogenation of aromatic compounds. comprising oxidati e dehydrogenating a compound selected from the group consisting of l nuclear substituted ethyl benzene having the formula:

(H (it, (l)

(wherein X represents a lower alkyl radical or a halo gen atom) and (Z) cumene or a nuclear substituted cumene having the formula:

(wherein Y represents a hydrogen atom. a lower alkyl radical or a halogen atom),

said dehydrogenating being carried out at a temperature otfrom about 350 to 550C in the presence of an oxidizing agent selected from the group consisting of oxygen, air and a mixture of gas containing oxygen or air and nitrogen or water and a phosphorus tin aluminum oxide catalyst composition comprising from about l0 to about 40 weight percent phosphorus calculated on the basis of P 0 from about It) to about 40 weight percent of tin calculated on the basis of Sn(). and from about 40 to about weight percent of alumi num calculated as Al O said catalyst composition being prepared by mixing alumina sol or aluminum by droxide. tin hydroxide and phosphoric acid at a predetermined ratio so that elementary phosphorus-tinaluminum composition of catalyst finally obtained is within the aforementioned weight percents; and then calcining the resultant mixture; the ratio of the amount of catalyst composition to the amount of reactant sup plied per hour in said process being from about l.0 to l5.0 gmolhhr, and the partial pressure ratio of reactant aromatic compound to oxidizing agent being from about 1/02 to 1/15.

2. The process according to claim 1. wherein said process is carried out at a temperature from about 400 to 450"C 3. The process according to claim 1, wherein said process is carried out at a ratio of catalyst to reactant per hour is from about 5.0 to about 10.0 gmolhhr.

4. The process according to claim I, wherein the said partial pressure ratio of aromatic reactant compounds to oxidizing agent is from about 1/05 to about l/LO. 

1. A PROCESS FOR OXDATIVE DEHYDROGENERATION OF AROMATIC COMPOUNDS, COMPRISING OXIDATIVE DEHYDROGENATING A COMPOUND SELECTED FROM THE GROUP CONSISTING OF (1) NUCLEAR SUBSTITUNATED ETHYL BENZENE HAVING THE FORMULA:
 2. The process according to claim 1, wherein said process is carried out at a temperature from about 400* to 450*C.
 3. The process according to claim 1, wherein said process is carried out at a ratio of catalyst to reactant per hour is from about 5.0 to about 10.0 g.mol 1.hr.
 4. The process according to claim 1, wherein the said partial pressure ratio of aromatic reactant compounds to oxidizing agent is from about 1/0.5 to about 1/1.0. 